The developments of safe and novel methodologies that can be used in vivo in humans are of utmost importance to advance our understanding of the pathophysiology of sensory and motor disorders of the human esophagus. Equally important is the ability to raise key questions that can be answered using novel methodologies in humans where one can study the diseased state as well as find possible targets for pharmacology and surgical therapy. During last funding period we used high frequency ultrasound imaging in a creative fashion to study the following: 1;biomechanics of the wall of the esophagus in relationship to its sensory and motor function, 2;muscle hypertrophy in spastic motor disorders of the esophagus (nutcracker esophagus, diffuse esophageal spasm and achalasia of the esophagus) and 3;longitudinal muscle function and dysfunction of the esophagus in health and disease. Our group has identified novel targets for esophageal sensory and motor dysfunction, i.e., sustained contraction of longitudinal muscles of esophagus as a motor correlate of esophageal pain and hypertrophy of the esophageal musculature in spastic motor disorders of the esophagus using high frequency ultrasound imaging of the esophagus. The specific aims of our studies during next funding period are to determine: 1, the effects of muscle hypertrophy on the biomechanical properties of the esophageal wall in relationship to esophageal sensation, 2, the incidence of muscle hypertrophy in patients with esophageal symptoms, 3;biomechanical properties of the esophago-gastric junction (EGJ) in normal subjects and patients with muscle hypertrophy, 4;synchrony and asynchrony between circular and longitudinal muscle layers during peristalsis in normal subjects and patients with motor disorders of the esophagus respectively. We believe that our studies will provide new directions to an area of important clinical significance.